The present invention relates to an electrical system for improving the quality of electrical power that is fed into electronic or other electrical equipment or into electrical or electronic components within electronic or electrical equipment. More particularly, the present invention is directed in general to usage on A/C operated devices, preferably audio power amplifiers and pre-amplifiers, televisions (TVs), recording studio amplifiers for musicians, computers, computer peripherals, electrical motors, air conditioners or other appliances, major and minor, and other such electronic and electrical equipment, but not limited to them exclusively. The present invention provides an effective interface for coupling electronic and other electrical components to the A/C line, effectively placing the electric utility transformer closer (from an electrical stand-point) to the electrical or electronic equipment receiving the A/C power. The invention further provides a quenching effect on line noise being produced by the equipment itself, which might effect other equipment sharing the same A/C power, and provides a relatively high current source and stores energy for, for example, power-hungry transients required by, for example, large power amplifiers in audio sound equipment and the like, without any of the xe2x80x9ctrade-offsxe2x80x9d of traditional power line conditioners.
A listing of prior patents, known to the inventor and which may be relevant to the invention, is presented below:
These patents generally are directed to audio amplifiers with transformer couplings, a completely different approach than that of the present invention which places an appropriate xe2x80x9cchokexe2x80x9d coil in parallel with the A/C power line, that is, across the A/C""s xe2x80x9chotxe2x80x9d and xe2x80x9ccommonxe2x80x9d or xe2x80x9cneutralxe2x80x9d lines.
The present invention is directed in general to usage in connection with A/C operated, electric or electronic equipment, preferably, for example, audio power amplifiers and pre-amplifiers, televisions, computers, computer peripherals, recording studio amplifiers for musicians, and other such electronic component equipment or other electrical equipment or devices, for example, electrical motors, air conditioners and other major and minor appliances, but the principles of the invention are even more broadly applicable.
It is noted that power amplifiers (and other high transient demand loads) and pre-amplifiers when providing an output signal to either the speaker (in the case of a power amplifier) or power amplifier (in the case of the pre-amplifier) tend to produce an undesirable, much smaller, mirror image of the signal that they are processing that modulates the A/C line source.
As an effective cure to this problem, the parallel choke approach of the invention, due to the fact that it must be magnetically charged by electricity [either from the A/C line or back electromotive force (emf) from it""s load] tends to have a reversing effect on this signal, preventing, eliminating or at least substantially reducing it""s presence on the A/C line, thereby providing a greatly enhanced, stablilzed, A/C power line signal for the load. Without the choke of the present invention, the otherwise untreated signals are able to modulate the A/C line, as it is resistive (basically a wire going from the utility services transformer to the wall outlet that the load(s) is/are plugged in to).
Up to now, with very few exceptions, virtually all line conditioners have been a major compromise when used in a line enhancement mode. They will in most cases remove small amounts of line noise generated on a given line by such things as motor starting, small transient disturbances and rarely radio frequency (RF) interference imposed on the line. They do this typically by placing small capacitors and air core or ferrite core chokes in series with the line, along with, for example, a metal oxide varistor (for surge suppression). This provides a low cost (high profit) solution to a very small problem.
In the last few years, research has shown that line borne interference is not the major cause of problems in, for example, audio systems. Further research has shown this to be true of other types of applications as well. It has been found that the equivalent series resistance (ESR) of the line is as critical as it would be in capacitive applications. This ESR is greatly aggravated by the majority of line conditioners, as they place resistive elements in series with the source and the load (the wall outlet and the amplifier). As such, when an amplifier hook-up attempts to produce an audio signal, it must discharge the capacitors contained in its power supply into the speakers. This audio signal is then used to modulate the speakers.
But, if one considers basic physicsxe2x80x94for every action, there is an equal and opposite reaction. In the case of an amplifier, the opposite reaction is the modulation of the power supply. No matter how large the power supply is, this modulation is unavoidable. In other words, part of the audio signal is imposed upon the line feeding the amplifier. This signal is then imposed upon other pieces of equipment in the system as well. Isolation transformers cannot stop this type of modulation, as they generally are barely large enough to keep up with the load they are supplying.
Now taking this analysis a few steps further, one should consider the amplifier as a large electric motor. When it tries to start, it produces a significant inverse transient on the line. As it spins up, this load lessens and the line then regains its amplitude. In the case of an electric motor, full rotor speed is (crudely put) the same as an amplifier idling, waiting for a signal. As the load engages the motor, it tends to become a greater load to the line and demands more current. As the audio signal is amplified by an amplifier, its power transformer becomes more of a load, and, therefore, places more of a load on the line.
To make matters worse, while the amplifier is struggling to deal with a resistive line and the further added resistance of any kind of line conditioner placed between it and the A/C receptacle, it is being subjected to all of the other components"" noises as well. To give an example of this, consider that a CD player is infusing various kinds of high frequency noise generated by its internal clock, as well as its processing circuitry. A VCR is as guilty as the CD player, as it probably uses a switch mode power supply and plenty of digital processing as well. If one is using a surround sound receiver and a television, the amount of noise is compounded in a source-by-source fashion.
It should be kept in mind that a prior art line conditioner does little or nothing to correct this kind of problem, and, as stated earlier, usually adds to the problem.
The present invention does much in the way of removing the effects of these problems. The exemplary embodiment herein actually provides a transient power supply when the need arises, as well as a blocking effect to the problems that are caused by the operation of electrical devices. It should be understood that, unlike power conditioning units and any transformer coil(s) used therein, the coil used in the present invention is not in series with the A/C line but rather is in parallel across the line.
Once one or multiple xe2x80x9cchoke coilxe2x80x9d units is cascaded or xe2x80x9cpiggy-backedxe2x80x9d or otherwise installed, the exemplary embodiment of the present invention effectively removes much of the problems caused by the ESR in the line and quenches much of the noise produced by the rest of the equipment as well. Bass signals becomes much clearer, imaging is improved, the color becoming richer and more life-like. In apartment buildings where electrical loading is a serious problem, as well as older houses that have marginal power connections, the exemplary embodiment of the present invention will have an even more dramatic effect.
With respect to computers and their peripherals, particularly a high usage piece, such as, for example, a laser printer that tends to produce problems when the fuser comes on, or such as, for further example, a copy machine that does essentially the same thing, the exemplary embodiment of the present invention make a great difference.
It should be understood that, although the foregoing analysis is directed primarily to audio equipment and the like, as an exemplary application, the benefits are similar in many other electrical/electronic applications.
Two additional patents considered in the parent application were U.S. Pat. No. 5,297,015 (issued May 22, 1994) entitled xe2x80x9cPower Supply Control Systemxe2x80x9d assigned to Hitachi, Ltd. of Japan, and 5,260,862 (issued Nov. 9, 1993) entitled xe2x80x9cA-C Power Line Filterxe2x80x9d assigned to Constant Velocity Transmission Lines, Inc. of Auburn Calif.
The Marsh invention is directed to a network (namely multiple ones) of frequency filter sub-circuits ganged in parallel to one another across the A/C line, each of which filter sub-circuits includes in series:
in all of its embodiments a capacitor serving a key filtering function, and an inductive coil with an open air core (FIGS. 3+), likewise serving a key filtering function, the capacitor and the inductor cooperating together to perform the filtering, and
in most instances (FIGS. 4+) a resistor (termed a RLC circuit), which frequency filtering network is described as collectively filtering out frequencies (xe2x80x9cnoisexe2x80x9d) above 60 Hz.
The values of the inductances are described in its only detailed embodiment (FIG. 9) as being in the relatively minute range of 0.5, 0.19 and 0.1 mh (milliheneries, i.e., thousandths of a henry, or, noting the presence of the decimal point, from 1 to 5 ten-thousandths of a henry (see column 3, lines 63-65). This is in stark contrast to the xe2x80x9cmassivexe2x80x9d (all claims) inductor coil of the disclosed embodiments of the Gray application which has an inductance of at least one henry (a comparative factor of about 1:10,000!) or more preferably at least 3 heneries (a comparative factor of about 1:30,000!) [Claims 5, 14, 23 and 24], with the massive coil core filled with magnetic or ferrous material with no capacitive element in its circuit at all.
Of course, in the context of the Gray invention and the Marsh patent, a factor of about 10,000 is not merely one of degree but rather one of kind. Additionally, the presence of a capacitor in series with the massive Gray inductor would be deleterious to its operation, preventing it from operating as described and claimed in this PCT application; the same is likewise true of adding a resistor in series with the capacitor and the inductor as taught in the Marsh patent.
In addition to these tremendous circuitry differences, the 60+ Hz frequency filtering function of the Marsh patent is neither the function, operation or effect of the present invention, which xe2x80x9c(quenches) the reflected back emf signal that develops when the electrical device load places its demands upon the incoming A/C power source line.xe2x80x9d Additionally, unlike the frequency filtering network of Marsh, in the Gray invention, xe2x80x9cthe electromagnetic characteristics of (the) massive inductive coil tend to provide a momentary high current source of energy when needed by the device load when transient demand signal is called forxe2x80x9d, and xe2x80x9calso tend to have a reversing effect on the. signal, at least substantially reducing the presence of the signal on the A/C line, providing a greatly enhanced A/C power line signal quality, without which the otherwise untreated signals would be able to modulate the A/C linexe2x80x9d. Likewise the Gray uses the xe2x80x9ccoil to substantially reduce, if not eliminate, the resistive effects of the wiring between the electrical device load and the (utility company""s) power transformer.xe2x80x9d
The relatively non-existent inductance, measured in the ten-thousandths of a henry, of the Marsh coils with its capacitors respectively in series are unable to perform these operations or effects. The presence of the capacitor in series with the xe2x80x9cinductorxe2x80x9d isolates the inductor, preventing the claimed xe2x80x9cquenchingxe2x80x9d effect of the Gray invention, and the presence of the series resistors provide a way for the emf to remain on the line in Marsh. The Marsh coils absorbs radio frequency energy in its filtering, while the Gray massive coil with its core of magnetic material stores magnetic energy. The minute amount of inductance and the presence of an air core in each of Marsh""s coils, which are immediately and easily saturated in the presence of, for example, 60 Hz A/C, do not allow them to store any significant energy, and therefore they cannot xe2x80x9csubstantially reduce, if not eliminate, the resistive effect of the wiring between the (utility company""s) transformer and the load.xe2x80x9d The Marsh circuit does not provide any current available to do anything, much less the specific operations of the Gray circuit. Indeed the Marsh circuit with its capacitors works against the alternating nature of the A/C line source, while the Marsh circuit performs its frequency filtering operation, while the Gray circuit, without any capacitor in its massive inductor line, allows and does not significantly hinder the rise and fall of the A/C power and actually through its xe2x80x9cflywheelxe2x80x9d characteristics or effect encourages the A/C line characteristics.
Ii is noted that the ""862 patent initially illustrates and describes a relatively simple circuit that has only one inductor coil (likewise in series with a capacitor) placed across the load between the AC power source and a load (note FIG. 1) and then presents a xe2x80x9ctest,xe2x80x9d which is graphically illustrated in FIG. 2, showing the impedance characteristics of the circuit, plotted against frequency, having a resonant frequency of xe2x80x9cFRxe2x80x9d some where above 60 Hz, with the circuit being capacitive in nature at frequencies below FR and inductive above FR. Although the circuit of FIG. 1 of the ""862 patent may superficially appear to be somewhat similar to the circuit of FIG. 1 of the instant PCT application, the embodiments of the present application, as noted above, do not include a capacitor in series with the massive inductive coil in its placement in parallel across and between the AC power source and the load. Additionally, the embodiments of the present application each include a core of magnetic material, while the inductor L of FIG. 1 of the ""862 patent does not, but rather is an xe2x80x9copen ailxe2x80x9d coil.
Additionally, the ""862 patent does not include the circuit of FIG. 1 as part of its invention, using it apparently only as xe2x80x9cbackground information,.xe2x80x9d and does not suggest that the circuit of FIG. 1 has any practical use at all!
Instead, as noted above, the Marsh patent is directed to a frequency filter network, using a multiple number of a capacitor/inductor in series, filtering sub-circuits of different frequency filtering characteristics (sometimes with an added series resistor and still in another embodiment a resistor in parallel to the inductor) in parallel to each other, to filter out frequencies (xe2x80x9cnoisexe2x80x9d) above 60 Hz. Several different embodiments of the xe2x80x3862 invention are shown in FIGS. 3, 4, 7 and 9, with their respective characteristics graphically illustrated in the other figures.
This ganged frequency filtering is not the approach of the Gray invention, which is directed to a totally different operation using a substantially different inductive circuit with a massive coil having a core of magnetic material.
Thus, the Marsh patent does not at all teach or suggest the present invention. As further discussed below, the ""015 Hitachi patent does not cure the Marsh deficiencies with respect to the present invention, and the combination of the two patents likewise do not fairly teach or suggest the present invention.
The Hitachi ""015 patent, nearly 50 pages in length, is directed to a relatively complex, xe2x80x9cpower supply control systemxe2x80x9d circuit in which there are a multiple number of loads with varying power input specification needs. All relevant circuits which use any form of a coil and a core illustrated in the fifty (50) figures of the patent only show only the use of a transformer (22/66) circuit, that is a coil with both primary and secondary windings positioned in series between the AC power source and the load(s). As noted in column 1, lines 27-31 of this patent and as is well knownxe2x80x94xe2x80x9cA conventional power supply system for distributing large power to a plurality of loads . . . supplies power from a commercial AC system to a load through a transformerxe2x80x9d. This, or course, is not like the circuit of the Gray invention which has only a single, continuous, inductor coil with only two terminal connecting leads and a magnetic material core placed in parallel across and between the AC source and the load(s)
The invention of the ""015 patent is designed to avoid the need of using different power conversion means to convert power into a form necessary for a particular load (such as, e.g., using individual switching power supplies, AC-DC converters, etc. as practiced in the prior art). It does this by including between the commercial AC power supply and the load a power supply control system including power conversion means and an interconnected control means which varies the power conversion means based on the power specification needs of the loads (FIGS. 47 and 48 provide the simplest illustration of this concept). In one embodiment through information means the load provides power specification needs to the system, which evaluates the needs and varies the power conversion means to provide the needed spec power.
This load-spec-informational/output-control approach of the ""015 patent is not what the Gray invention provides or even what Marsh""s frequency filtering network provides. Indeed, it appears that there is basically nothing in common substantively between the disclosures of the ""015 patent and the present, Gray invention or the Marsh patent. It thus appears that the Hitachi patent is not at all relevant on the issue of asserted xe2x80x9cobviousness.xe2x80x9d
Although the Hitachi patent does illustrates a DC output filter circuit 23F, the xe2x80x9creactorxe2x80x9d coil 25A is placed in series in one leg of a then DC power line and is used with a capacitor 26A across the DC power line legs (FIGS. 3A and 3B and column 8, line 51+; reactor 25 and capacitor 26, respectively, in FIGS. 10, 12 and 13), and this part of the Hitachi circuit and its operation and purpose are so diverse from either the Gray invention or the Marsh patent, it still appears to of no significant relevance to either the teachings of the Marsh patent (and its deficiencies with respect to Marsh teaching or suggesting the Gray invention) or the Gray invention itself. Regardless, any fair or reasonable combination of the two cited patents would not produce or teach the Gray claimed invention.
Thus, it would appear that the ""862 and the ""015 patents, whether taken individually or together in any fair combination, do not fairly suggest or teach the Gray invention, and that the Gray invention should be considered xe2x80x9cunobviousxe2x80x9d and hence patentable over these two patents.
Thus, the choke of the present invention, when placed in parallel with the A/C line as taught herein, provides a means of quenching the reflected signal (or back emf) that is developed when any power amplifier or other load places it""s demands upon the incoming A/C power line. It also, due to the electromagnetic characteristics of the choke, tends to provide a momentary high current source of energy when needed by, for example, a power amplifier (or other appropriate load) when transient demand is called for.
The preferred approach of the present invention places an appropriate xe2x80x9cchokexe2x80x9d coil in parallel with the A/C power line, that is, preferably directly across the A/C""s xe2x80x9chotxe2x80x9d and xe2x80x9ccommonxe2x80x9d lines. The coil preferably is relative massive but with relatively low ohmic resistance. To achieve this massiveness, the coil should have a thousand plus turns of wire (for example, about 1,310 turns) or its electrical equivalence, taking into account, for example, the gauge and conductivity of the coil wire, while having a relatively low internal resistance of less than one hundred (100 xcexa9) ohms, for example, more preferably about eleven (11 xcexa9) ohms. Such internal resistance is substantially less than most, if not all, of the equipment with which the coil will be used
The present invention provides an effective interface coupling electronic components to the A/C line, effectively placing the electric utility transformer xe2x80x9cphysically closerxe2x80x9d (in an electrical sense) to the electronic equipment, substantially improving the quality of electrical signal the electrical or electronic components xe2x80x9cseexe2x80x9d. The invention further provides a quenching effect on line noise being produced by the equipment itself and also provides a relatively high current source and stores energy for power-hungry transients required by, for example, large power amplifiers in audio sound equipment and the like, without any of the xe2x80x9ctrade-offsxe2x80x9d of traditional power line conditioners.
A review of the following will provide further clarifying information on the invention and its workings or mode of operation.
A television is probably one of the most complex loads an average consumer will ever place upon an A/C power line.
The modern television, compared with the older types of TVs, contain much more active circuitry. Technicians are constantly confronted with the statement:
xe2x80x9cmy old set lasted a lot longer and gave me no trouble. Why do I have more trouble with these newer sets?xe2x80x9d
If one considers what is going on in the new televisions, then one better understands, not only why new TVs break more often, but why the new (as well as the old) can benefit from the present invention.
Without the use of the present invention, a new, full feature television is a very complex load. When the set is xe2x80x9coffxe2x80x9d or in xe2x80x9cstandbyxe2x80x9d, as the state most of the newer sets resort to when they are turned xe2x80x9coffxe2x80x9d, typically the primary, if not only, circuitry operating is a small on-board computer, a switched mode power supply and, in some cases, a few relays that are used to select input functions.
Thus, this xe2x80x9cstandbyxe2x80x9d situation alone can impose a signal upon the A/C power line. The TV""s power supply is operating at minimum duty cycle, it""s switching pulses are short in duration. The computer has it""s clock operating and is awaiting commands. This provides at least two signals which are imposed upon the A/C power line even when the TV is xe2x80x9coffxe2x80x9d. So much for the diligent audiophile who turns his/her television xe2x80x9coffxe2x80x9d (standby) before listening, thinking that all interfering or line disturbing signals from the TV are xe2x80x9coffxe2x80x9d.
One should then also consider what occurs when the television is turned xe2x80x9conxe2x80x9d, and, for example, the associated home theater is completely engaged. First, the main oscillator is activated by the on-board computer. This excites the horizontal circuitry, which is used to produce not only the high voltage and high amplitude waveforms that are needed for CRT scanning, but also the scan type power supplies used to power the other circuitry. Vertical sweep is now started, usually provided by a master oscillator divided by other circuitry and then amplified by a small power amplifier, which is then coupled to the deflection circuitry.
While all this occurs, color circuitry is operating, as well as video and the delay circuitry. Audio, usually treated as a xe2x80x9cstepchild, xe2x80x9d is also brought on at this point, or as soon as a signal is detected from the tuner and mute is released.
As the television reaches full function, all of the circuitry just discussed is now imposing it""s noise upon the main power supply, and it, in turn, places it""s noise and all the rest (in smaller amounts) also upon the A/C power line, which, of course, is servicing other electrical loads and electronic components.
The xe2x80x9csurround soundxe2x80x9d decoder, line doubler (in the case of big screen types) and all of the associated audio support pieces likewise all have their signals imposed on the A/C power line. This can, in some cases, actually become noticeable in the degraded quality of the audio and picture that the system can produce.
The present invention can effectively prevent the components from cross-talking on the A/C power line. Not only do all the components benefit from the reduction of this cross-talk, but the power supplies on all of the associated equipment perform more effectively and efficiently. The lost signal (i.e., lost in the line and confused with other signals) is now presented to the viewer in dramatic fashion. The color is truer, as well as the overall detailing of the picture is improved.
Additionally, for tube (versus solid state) equipment, used, for example, in amplifier circuits, the tubes tend to run cooler and last longer, effectively extending the service life of the equipment.
Test demonstrations on lower-end televisions with an embodiment of the present invention showed that the invention provided dramatic effects, as well as when used on high end and projection type television.
It is noted that, because the main A/C supply is simply an error corrected type of supply, the error must actually be present long enough for the error correction circuitry to detect and process the information, this being controlled by the time constant of the feedback loop contained in the power supply. Before the correction can occur, the signal that is creating the error is passed along to the capacitor supply that resides in the main supply, this capacitor being depleted of a good deal of it""s charge before the duty cycle of the power can correct for this.
Without the present invention, the horizontal sweep frequency, (which appears as an error to the main A/C supply under high demand, as described earlier), the main power supply switching frequency and the variation of its duty cycle as it tries to correct for the added load from a bright scene (also described earlier) are now all passed along to the primary power source, namely, the A/C line. Once the television returns to a more average type of picture, the power supply once again passes errors along to the A/C power. line.
Since the power supply is working at an increased duty cycle, once the load on it is reduced, the error correcting circuit must once again detect the lessening of the load and compensate for it. This is passed on to the line also, but as a momentary lessening of the load or an inverse fingerprint.
Once the embodiment of the present invention is installed on the A/C power input line, these xe2x80x9cfingerprintsxe2x80x9d are greatly reduced. Also, the main power supply has a greater amount of energy to draw from, thus aiding in reducing the errors passed through the power supply, giving the error correction circuitry much less work to do. (It should be remembered that, if the signal is imposed upon the line, the power supply must work to compensate for it, as well as the primary error or xe2x80x9cdemandxe2x80x9d imposed upon it.)
The more of today""s components (e.g., line doublers, super tube and big screen televisions, high resolution and multi-function VCR""s, high power audio amplifiers, surround sound decoders, laser disk and DVD, remote controlled pre-amps, cable and satellite receivers, etc.) that are installed in homes and business, the more the present invention becomes a necessity. Since all of these products all produce their own electrical xe2x80x9cfingerprint,xe2x80x9d a line supply that is resistive like that found in most homes is quite ineffective. As the line is further worsened by many of the xe2x80x9cline conditionersxe2x80x9d that abound on the present market, these fingerprints become more and more evident.
The preferred embodiment of the present invention effectively removes or quenches most of the signals modulating the A/C power line, as well as providing a very high short term type of power supply for the more demanding of those components.
In the case of the larger screen televisions, a bright scene will usually place quite a demand upon the power supply, as well as the high voltage supply. Since the high voltage supply is operated as a form of switched mode supply and under a heavy load, it passes its demands along to the main supply, and it too, in many cases, is another form of switched mode power supply.
Considering that as the main supply is simply an error corrected type of supply, the error must actually be present long enough for the error correction circuitry to detect and process the information, this being controlled by the time constant of the feedback loop contained in the power supply. Before the correction can occur, the signal that is creating the error is passed along to the capacitor supply that resides in the main supply, this capacitor being depleted of a good deal of it""s charge before the duty cycle of the power can correct for the error.
Without the present invention, the horizontal sweep frequency, (which appears as an error to the main supply when high demand, as described earlier) the main power supply switching frequency and the variation of it duty cycle as it tries to correct for the added load from a bright scene (also described earlier) are now all passed along to the primary power source, namely, the A/C line. Once the television returns to a more average type of picture, the power supply once again passes errors along to the A/C line. Since the power supply is working at an increased duty cycle, once the load on it is reduced, the error correcting circuit must once again detect the lessening of the load and compensate for it. This is passed on to the line also, but as a momentary lessening of the load or an inverse fingerprint.
Once the preferred embodiment of the present invention is installed on the line, these xe2x80x9cfingerprintsxe2x80x9d are greatly reduced; also, the main power supply has a greater amount of energy to draw from, thus aiding in reducing in the errors passed through the power supply, giving the error correction circuitry much less work to do.
All of this only explains the horizontal sweep demands and its problems with operating on an adequate A/C line. As the line becomes more and more poisoned by the resistance within it, enabling the modulation of itself by the loads imposed upon it, one must consider the effects of having an entire audio/video home theater and possibly other loads (air conditioning, etc.) upon the line as well.